Re: [PATCH 3/3] softirq: Use const char * const for softirq_to_name, whitespace neatening

[Joe Perches <joe@perches.com>]

On Tue, 2013-12-24 at 23:19 +0800, Wang YanQing wrote:
> On Sun, Nov 17, 2013 at 01:55:12AM -0800, Joe Perches wrote:
> > Reduce data size a little.
> > Reduce checkpatch noise.
> > 
> > $ size kernel/softirq.o*
> >    text	   data	    bss	    dec	    hex	filename
> >   11554	   6013	   4008	  21575	   5447	kernel/softirq.o.new
> >   11474	   6093	   4008	  21575	   5447	kernel/softirq.o.old
> 
> Hi, could you tell me why this patch could reduce data size?

It moves the softirq_to_name array of 10 char *
from data (non-const) to text (const).

-char *softirq_to_name[NR_SOFTIRQS] = {
+const char * const softirq_to_name[NR_SOFTIRQS] = {
        "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
        "TASKLET", "SCHED", "HRTIMER", "RCU"
 };

Use objdump or "make kernel/softirq.lst" and inspect
the object code produced to see for yourself.

cheers, Joe